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=============================================================================
FreeBSD-SA-00:18                                           Security Advisory
                                                                FreeBSD, Inc.

Topic:		gnapster/knapster ports allows remote users to view local files

Category:	ports
Module:		gnapster/knapster
Announced:	2000-05-09
Reissued:	2000-05-16
Credits:	Fixed by vendor.
		Knapster vulnerability pointed out by:
		Tom Daniels <daniels@CERIAS.PURDUE.EDU> via BugTraq
Affects:	Ports collection.
Corrected:	2000-04-29 (gnapster)
		2000-05-01 (knapster)                
Vendor status:	Updated version released.
FreeBSD only:	NO

I.   Background

Gnapster and knapster are clients for the Napster file-sharing network.

II.  Problem Description

The gnapster port (version 1.3.8 and earlier), and the knapster port
(version 0.9 and earlier) contain a vulnerability which allows remote
napster users to view any file on the local system which is accessible
to the user running gnapster/knapster. Gnapster and knapster do not
run with elevated privileges, so it is only the user's regular
filesystem access permissions which are involved.

Note that there may be further undiscovered bugs in these and other
napster clients leading to a similar vulnerability. System
administrators and users should exercise discretion in installing a
napster client on their system.

The gnapster/knapster ports are not installed by default, nor are they
"part of FreeBSD" as such: they are part of the FreeBSD ports
collection, which contains over 3200 third-party applications in a
ready-to-install format. The ports collection shipped with FreeBSD 4.0
contains this problem since it was discovered after the release.

FreeBSD makes no claim about the security of these third-party
applications, although an effort is underway to provide a security
audit of the most security-critical ports.

III. Impact

Remote users can view files accessible to the user running the
gnapster/knapster client.

If you have not chosen to install a napster client, then your system
is not vulnerable to this problem.

IV.  Workaround

Deinstall the gnapster and/or knapster port/package, if you you have
installed them.

V.   Solution

One of the following:

1) Upgrade your entire ports collection and rebuild the gnapster
and/or knapster port.

2) Reinstall a new package dated after the correction date, obtained from:

[gnapster]
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/audio/gnapster-1.3.9.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/audio/gnapster-1.3.9.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/audio/gnapster-1.3.9.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/audio/gnapster-1.3.9.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/audio/gnapster-1.3.9.tgz

[knapster]
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/audio/knapster-0.10.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/audio/knapster-0.10.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/audio/knapster-0.10.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/audio/knapster-0.10.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/audio/knapster-0.10.tgz

3) download a new port skeleton for the gnapster/knapster ports from:

http://www.freebsd.org/ports/

and use it to rebuild the port(s).

4) Use the portcheckout utility to automate option (3) above. The
portcheckout port is available in /usr/ports/devel/portcheckout or the
package can be obtained from:

ftp://ftp.freebsd.org/pub/FreeBSD/ports/packages/devel/portcheckout-1.0.tgz

VI.   Revision History

v1.0  2000-05-09  Initial release
v1.1  2000-05-16  Update to note that knapster 0.9 is also vulnerable and
                  broaden warning to include all napster clients.
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